Refrigeration apparatus



aiemed June' 3o, 1942 UNITED STATESPATENT OFFICE 'jnEFn'IGERATIoN APPAnA'rJs l Orton S. McGufl-ey, Lansing,. Mic assignor to Kold-Hold Manufacturing Company, Lansing,` Mich.; a corporation of M .ichigan applicati@ May 31, 194e, vserial No. 33ans 4 claims. (ci. s2-95) This invention relates to. refrigerating appacasesat one edge, is thelast to fre ze. This is ratus of the hold-over type, and particularly particularly true in the cornerswhere the greatto the refrigerating -units used i in connection est wall surface per unit of volume is present; therewith. i Such -a condition is harmful for this reason.

Refrigeratlng apparatusv of the holdover 5 The solution within the container has' charac- 'A type includes one or more-refrigerating units. terlstics similarto water. As the temperature of Each unit comprises a sealed containen'an evapthe solution decreases, its 'volume decreases until orator coil inside of the container, and a quan'- the temperature nears the freezing vpoint of the tity of freezable solution within` the container solution. Thereafter the 'solution expands very and 4surrounding the evaporator coil. Usually 10 sharply until it solidiiies. When freezing first f the container is substantially in thershape of a occurs near the center of the container and proat rectangular parallopiped, as that shape has gresses outwardly therefrom,I the final expanbeen found to have a particularly highefciency.` sion takes .place at the edgeswhere the con- The evaporator coil consists of a continuous tube f tainer walls have little flexibility. vThe unit Y bent into serpentine. formand having its ends l5 stress in the container walls is thus very high. in

brought out through a wall of the container.l fact,' more than the elastic limit of the 'material The coil/is adapted to be"connected to a refrigin the walls. Repeated freezing and melting of erant source-such as a compressor. The freez-l; the solution will eventually cause the side walls able solutiorris preferably a eutectic. Y to rupture and leakage will occur. This is true The freezable solution is frozen into ice by 20 whenever small quantities of solution are trapped connecting the evaporator coil Ito a compressor adjacent the side walls, no matter how freezing and passing ammonia or otherjrefrigerant progresses elsewhere within the container. through the coil. After the` ice is formed the Therefore, the principal object of this invenow of refrigerant is stopped? The melting ice tion is to provide a refrigerating unit ofthe type cools the space surrounding the`refrig`erating 25 mentioned which will not fail from repeated unit. freezing and thawing of the solution. This'ob- This type of refrigeration is particularly useject is attained by .shaping the container and ful in the transportation eld as it eliminates the arranging'the evaporator coil therein in such Aa necessity of carrying a compressor on the truck, manner that freezing will lrst occur adjacent railway car, or other vehicle. The solution may 30 the edges of the container, and as freezing probe frozen at any convenient place, the compresf gresses the unfrozen liquid will migratel toward sor disconnected, and during the' trip the melt-f. the center of the container. The last liquid to in'g ie keepsV the vehicle at the proper' temperafreeze will then-be in the central part of the ture. f container and when it expands the force exerted Heretofore dilculty hasbeen experienced with\'?3` 5 against 'thel container. walls will lbe distributed apparatus of the type mentioned because ofthe overa large wall area. Consequently, the unit rupturing of the containers after a relatively stress in the walls will'not exceed the elastic short. period of use.IV This is dueto the stressing limit offthe material of which they are composed.

vof the. container walls beyond their elastic limit Another object of the invention, is the proviwhen the solution solidies and forms ice. 40 sion ofa container which can be easily and eco- In a refrigerating unit of2 the type mentioned, hnomically manufactured.l i

that is, a unit in which the container is relatively Still another object is the provision 'of' a novel shallow, considerably more surface per unit of form of heat conducting iin which is readily atvolume is exposed at the edges' than ln the centachable tothe freezing coils. trai part of the continei Since the walls of the 45 These objects will more fully, appear in the container'fhave a high heat conductivity, heat following specification when read in.connection i'sabscrbed and transmitted to the solution at with the accompanying drawing, whereinthe edges more rapidly than to the liquid in the Figure 1 is a fragmentary front elevational center. As a result '.thevsoluton at the edges view of a. hold-over refrigerating unit embody--`l ofsthe container is more diiiicult'to freeze and 50 ing the invention; -Wheh frozen) melts more quickly than that in -Figure'2 is a side elevational view of the device the center part. Therefore, afrequent occur- L shown in Figure 1; H

. rence in units of this tie is that the liquid about Figure 3 is -a cross-sectional View taken on the coils in` the vcentral part of' the container substantially the line 3-3 of Figure l;

vfreezes'first and that at the edges, or in sme 55 Figure'4 is a fragmentary cross-sectional view l shape shown in Fig. 1.

The container is made up of two shallow panlike ,metal stampings. The stampings are practically identical. Each stamping consists of a large flat wall I2, an u pturnedl side wall I3, and a marginal flange I4. The side wall I3 is curved in (cross section (see Figures 3 and 4) and merges ,smoothly into the large flat`w'all I2 about the yperiphery of the latter. Three corners of the stamping aresmoothly roundedon curves of relatively great radii. f

The fourth corner I5 is not rounded, as is the case with the other three, but is formed at an angle, preferably 45, to the adjoining sides of thel stamping. Furthermore, the side wall I3, at the corner I5, is` pressed out at two spaced points to form a pair of semi-circular anges 26 and 21,

` for a purpose which will appear presently.

'The flange I4 is of uniform width along the straight sides of the container, but the ange is eliminated at the corner I5 and is of reduced width at the other three corners. This reduction in width isaccomplished 4by curving theedges of the flange on a radius greater than -that of the rounded corners.

The two /stampings are arranged in inverted relation to each other with their open sides to' gether. The flanges I4 are seam welded together, and the edges of the walls I3 at the corner I5 are butt welded together. [It will be noted that when the stampings are secured together the semi-circular flanges 26 and 21 in the corners I5 are superimposed, thereby forming a pair ofl openings through the side wallA of the container.

The evaporator coil II- within the container comprises a tubular coil bent into the serpentine The coil winds about within the container and forms an outer, Vnearly closed, loop I6, then a series of narrow U-shaped loops I1,fand terminates in a wide U-shaped loop I8 between the loop I6 and the loops I1.

The loop I6 is concentric with the side walls of the container and as'close thereto as it can be. The loop I8 is just within and concentric with three sides of the loop I6. The other -loops I1 .are `spread uniformly throughout the remaining space. f The ends of the coil IIfare connected to a pair of elbows i9 and 20. The outer ends of the elbows t within the yopenings between the flanges 26 and 21 at the corner. I5 and are welded'to the flanges. The elbows are internally threaded toV4 receive removable plugs 2| or connections from a suitable refrigerant compressor system.

On the opposite sidesvof the coil. II are' a plurality of channel members 22 which serve the dual purpose of holding various passes of the and are` welded or otherwise secured together. -When the channels 22 are thus secured together the arcuate grooves in the webs are in contact with the walls of the coil tube. The flanges of the channels 22 project outwardly into contact with,,or at least closely adjacent to, the walls I2 and I3 of the container.

The container is about 90% filled with a suitable freezable eutectic solution, through ller holes 25 in the wall I2. The holes 25 are then plugged.

When in use the elbows I9 and 20 are connected by suitable pipe fittings to a compressor,

I 5 freezes first, and fills the space at the sides and in the corners of the container with ice before the solution freezes suiiiciently elsewhere to trap any isolated liquid. This initial freezing is quite uniform because of the concentricity of the loop I5 with theside walls I3 and cornersv of the container, as well as because the reduction in width of the flange I4 at the corner equalizes the exposed metal surface about the periphery of the container.

Thereafter, as freezing continues, the unfrozen liquid tends to migrate toward the center of the unit vand eventually just before the solution becomes completely frozen all of the solution which remains in a liquid condition will be contained within a zone at the center of the container.

When -this solution freezes it will expand and exert a pressure againstlthe opposite large walls I2 of the container. However, the latter are free to bulge outwardly to permit the expansion without' exceeding the elastic limit of the material.

. Thus it will be seen that with the construction described there is no possibility of pocketing small quantities of liquid in the container in zones where the walls are not free to take care of the expansion.- As a result, the container will never become unfit for use by reason of bursting of the side walls. Furthermore, the container is readily manufactured from but two simple and easily formed metallic stampings. The corners and sides of the container walls are smoothly rounded and there Ais little likelihood of the metal coil in proper relationship to the container and to each other, and of absorbing heat and transmitting it to the coil.

The webs of the channel members are provided at spaced intervals with transversely extending arcuate grooves 23 to receive the outer walls of the tube forming the coil II. The webs are also provided .adjacent their ends with a pair of bosses 24. The bosses project outwardly from the channels are mounted ,web to web, as shown the webs of the channels far enough so that when tearing in the diesin which the halves of the container are formed. It will also be seen that the heat absorbing 4fins employed in connection with the evaporator coil are relatively simple and easily and economically fabricated and assembled.

- The scope of the invention is indicated in the appended claims.

'I claim:

1. A hold over refrigeration unitvincluding, in combination, a sealed sheet metal tank having closely spacedopposed side walls of relatively large area, the interior of' said tank being free from abrupt corners and being substantially disposed within the tank in spaced relation to' said side walls and having inlet and outlet endsV communicating with the exterior of the tank,

said evaporator tube including a portion extending substantially around the perimeter of the tank in closely spaced relation thereto and other portions distributed substantially uniformly. throughout the remainder of the tank, the first portion being arranged to receive refrigerant before said other portions and the maximum distance between the said rst portion of the tube and the adjacent walls of the tank being substantially less than the maximum distancebetween any other portion ofthe tube and the walls of the tank adjacent thereto.

2. A hold over refrigeration unit including, in combination, a sealed sheet metal tank having opposed side walls of relatively large area, said over solution,I and an evaporator tube disposed tank including a zone extending around the tank Y adj acent its perimeter of'a smaller internal crosssectionalarea than that of the remainder of the tank, the interior of said tank being free from abrupt corners and being substantially filled with a freezable hold over solution, and an evaporator tube disposed within the tank in spaced relation to the side walls thereof and having inlet and outlet ends communicating with the exterior of the tank, said evaporator tube 'including a lrst portion disposed in said zone of reduced crosssectional area and extending substantially around the perimeter of the tank, said evaporator tube including other portions distributed substantially '4 uniformly throughout the remainder of the tank,

the said first portion of the evaporator tube being arranged to receive refrigerant before said other portions. A

3. A hold over refrigeration unit including, in combination, a sealed sheet metal tank havingclosely spaced opposed side walls of relatively large area, said tank being of substantially uniform internal cross-sectional area. in the central portion thereof and of .gradually decreasing crosssectional area toward the perimeter in the region of the perimeter thereof, the interior of said tank being free from abrupt corners and being substantially filled witha freezable hold within the tank having inlet and outlet ends communicating withthe exterior of the tank, said evaporator tube including a'iirst portion disposed in said zone of gradually decreasing crosssec tional area and extending around the perimeter of the tank in closely spaced relation thereto, said evaporator tube including other portions distributed substantially uniformly `throughout the remainder of the tank, the said rst portion of the evaporator tube being arranged to receive refrigerant before said other portions.

4. A hold over refrigeration unit as vdefined in claim 3 wherein the spacing between the said rst portion of the evaporator tube and the walls of the tank is closer in the region of the smallest` cross-sectional area than in the other regions of the tank and wherein said other portions of the evaporator tube are spaced at least as great a distance from the adjacent walls of the tank las the maximum spacing of said first portion from the walls ofthe tank amacent thereto.

ORTON S. MCGUFFEY. 

